Is Eating a "Waste" of Time?

I did a little project a couple of years ago on student misconceptions and the conceptual change model. I chose to do my lesson plan on digestion, specifically the fate of the food we eat. In my preliminary research, I found that many students have this idea that the food is eaten, goes through the digestive system, and emerges as waste from the anus (giggles all around). When asked about how much of the original food leaves the body, the numbers were extremely high - 50%, 90%, even 100%. This is quite understandable given our personal experience with said waste and no way of explaining the volume of it produced. Students have this abstract idea that food is needed for energy, but for all they know we somehow extract the energy (whatever that is) from food in the digestive system itself and then eliminate the food when we're finished "using it." Few students seemed to have any conception of how the food is used for growth, maintenance, repair of our own tissues/cells or what energy is. There are a lot of lessons suggested by these misconceptions, but at the time I was taking this class I was required to produce a single lesson plan that would address the misconception. I don't think it was very effective.

For my regents classes I wanted to start with the misconception, so the title of this post was my AIM. As a DO NOW I asked students to describe the fate of food from start to finish, expecting the misconception again to come out in their responses. They were however a little too saavy and mostly mentioned the part about breaking down food into smaller particles that were absorbed into the bloodstream and carried to the cells.

From the misconception, I planned a short project for students to do some cooperative group work, researching the structure and function of various parts of the disgestive system, jigsawing with other experts, then re-convening to put it all together into a coherent narrative. As part of the project, students will construct a scale model of the digestive system - schematically conceived - and use the model as a prop when they present. Each person in the group is responsible for detailing the fate of one nutrient - carbohydrate, protein, lipid. Here are the details:

A JOURNEY INTO THE DIGESTIVE SYSTEM & BEYOND

Your Task

1. Describe the fate of one nutrient in the human body:


a. A protein


b. A fat/lipid


c. A carbohydrate – starch


d. A carbohydrate – sugar.


e. A carbohydrate – fiber

2. Describe what happens if something goes wrong in the digestive system

--Describe real conditions that affect humans.

3. Create a scale model of the digestive system using everyday materials such as
cardboard, fabric, paper, etc.

Procedure:

1. Form groups of 4.

2. Each group member will become an expert in one of the following parts:


a. Mouth & Esophagus


b. Stomach


c. Small Intestine


d. Large Intestine & Accessory Organs (Liver, Pancreas)

3. Jigsaw: At different times, experts for each part of the system will get together to share notes. Then you will return to your main group. Since the different parts of the system work together, you will need to understand how all the parts work together. (See details)

4. Create a storyline detailing what happens to your nutrient. (See details)

5. Create a scale model of the digestive system. (See details)

Presentation:

Each group will have a 5-minute presentation. You will use the scale model as a prop to help you tell the story of your nutrient. (See rubric).

I will post some more of the details as we progress. Here are the original questions I've asked students to research:

Part 1: Basic Research (Use extra paper if needed)

• What does digestion mean?
• What is the basic structure and function of your organ/organs.
• What is the organ made of (what kinds of cells, tissues, etc)? What does the organ do?
• What do the specialized parts of the organ do?
• What does the food look like before it is worked on by your organ? After?
• What kinds of nutrients are digested by your organ/organs?
• What is the sequence of events within the whole digestive system? (Numbered list.)
• What happens if some part of your organ/organs malfunction? Explain, name a disorder.
  
  

Creating Models as Inquiry Process

It's been a terrily busy week with class & parent teacher conferences and the like.

OK, so I presented the DNA modeling activity in my curriculum & instruction class Monday night. I'm still not clear in my mind to what extent the activity is an inquiry activity. I got some good suggestions (below) on how to make it more of an inquiry activity, but as it was carried out I remain skeptical.

First, what is inquiry? One of my problems with this term is that it means so many different things to so many people. In order to answer address the question, "Is it inquiry?" you first have to define the term.

I like the inquiry framework on the TIEE website that shows inquiry as a sort of continuum with totally directed instruction at one end and open ended inquiry at the other. I suppose one could argue for this type of modeling activity to fit within their "guided inquiry" definition based on the level of student ownership - in this case, that was basically in the analysis & presentation column. Everything else was pretty much given - the question, the method, & the "data collection," which didn't really apply in this activity. In the future I would take some suggestions from my classmates and allow students more freedom in devising a model of their own. I would have the following conditions, the students would decide how to meet those conditions:

1. Must be a model made up of repeating parts, just like real DNA. In other words, must be made by linking together 2 separate strands, each strand made of distinct phosphate groups, sugars, bases. May be organized into nucleotide groupings, but...

2. Must be able to replicate by "unzipping" and then adding nucleotides.

3. Must have a color code for the base pairs.

4. Must have the basic shape of a segment of DNA - "ladder" - not necessarily helical - for this activity.

I might refine the criteria a little more before I have to teach this again next year.

A final note. The definitions of inquiry on the TIEE site and others often seem to be limited to studies that require the gathering of data to answer a research question. However, making models is clearly a part of what scientists do (even if it's just a preliminary step toward formulating research questions & hypotheses) and the NY State intermediate level standards include making models:

Interconnectedness

Key Idea 2:

Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design.

2.1 Select an appropriate model to begin the search for answers or solutions to a question or problem.

2.2 Use models to study processes that cannot be studied directly (e.g., when the real process is too slow, too fast, or too dangerous for direct observation).

2.3 Demonstrate the effectiveness of different models to represent the same thing and
the same model to represent different things.

Again, not to be pedantic, but these standards for modeling are not included in the "inquiry" standards but the "interconnectedness" standards. It seems to me if the word "inquiry" is to have any meaning, then it cannot be so broad as to lose all it's original meaning related to "inquiring" or asking questions. My bottom line feeling, and I'll stop here, is that in the usual educational all-or-nothing approach to teaching strategies, a lot of useful and important science teaching practices were being cast aside because they weren't "inquiry." Now the desire to include those useful strategies has resulted in a broadening of the term inquiry to include those strategies. The way I see it, building models may be part of an inquiry activity if the model is used to generate questions & hypotheses that CAN be investigated, but the model-building itself only fits within a rather loose definition of inquiry.

(It's getting late & I'm talking off the top of my head. Maybe I'll continue this train of thought & put more research into it for my final paper.)

Expenses Update

In a previous post I discussed some of the extra costs of teaching and vowed to keep a running log. I'm having trouble keeping up with some of the nickel & dime stuff, so I'll just have to estimate. By nickel & dime, I mean the occasional candy or (more rarely) soda that I buy for my helpers and sometimes grocery store/$.99 store lab materials like seeds, cups, pasta, etc. I do have a few larger expenses to add to the total:

Previous total: $347.00 (I'm also rounding off from now on)

Pizza partys for both regents classes: $150.00 (including sodas, delivery tip, etc.)

Computer cable for scanner: 10.00

Stenographer pads for use as Exit Project Journals x 60 = $55.00

2 cases Staples multipurpose paper: $38.00 (sale price)
Nickel & dime since September: 100.00

Total: $700.00

Part A Lab Report: DNA Structure

For future reference - click on the picture which links to the related post.

And here's a student lab sheet. This is the one where I asked the students to compare the model to reality. Interestingly, today we viewed a portion of the PBS/NOVA video: Cracking the Code of Life. The scientist in the opening scenes doesn't do such a good job of describing how DNA is different from the 3D model being displayed by the program's host. (Don't ask me for names, it's been a long week!)

UPDATE: The scientist is Eric Lander, Director of the MIT Center for Genome Research, and the correspondent is Robert Krulwich, whom you may remember as an ABC Nightline correspondent. Lander does note that the model looks like DNA in a "cartoon" sort of way, but doesn't elaborate.

!

The kids still have a hard time with the concept of scale. The student here is trying to express an idea we discussed in class, but she doesn't completely understand it yet. Namely, in one sense our model is much bigger than real DNA, in an obvious sense. In another sense, it is much smaller - we have only 5 base pairs in our model, where a single strand of DNA contains 10's of millions of base pairs. If our model had that many base pairs (using pasta & pipe cleaners) it would be over 1000 miles long! We actually did the math on this in class. Some of the students totally misinterpreted this number - "Wow, you mean we have 1000 miles of DNA in one cell" Well, no, if we enlarged a strand of DNA to the size of our model, it would be 1000 miles long...etc. Actually the fact that the DNA in one cell laid end to end would equal about 2 meters is pretty mind boggling in itself. Just multiply that 2 meters by the 50 trillion or so cells in our bodies, and that's a pretty significant distance also! (100 trillion meters = 100,000,000,000 Km = 62,000,000,000 miles roughly).

I probably went overboard with some of the DNA material, but it's hard to gauge how far to take it. The last exam (January 2005) is pretty heavy on the genetics material, I plan on using the questions for their unit test tomorrow. We'll see how they do.

UPDATE

Pasta DNA Models

I can't remember where I got this idea from, but I needed some easy & cheap way for students to be able to create a concrete model of DNA. Pictures in a book just don't do it. So we created these models with pipe cleaners & pasta.

Students used penne for the phosphate group, fiori make the sugar, pipe cleaners of different color make the base pairs. String binds the pieces together. We used the models to visualize the structure, and to simulate replication. Below is a sample of a lab sheet produced by a student. I did not choose the absolute best example - it has some deficiencies, but it's pretty good.

Updated:

I also asked (as I always do) students to consider how the model is accurate and how the model "fails" (I left that part off the lab sheet).
I actually included the question on comparing model to reality in part A, which I will scan later today. This scan shows part B, in which we replicated our pasta DNA. The drawings are simplified, I did not want them spending time drawing pasta shapes where the emphasis was on the process rather than the structure.

(Click on picture for larger view)

I will discuss the concerns I have about teaching molecular genetics in a subsequent post. I have a lot of concerns about how to teach the subject using an inquiry approach, although one could argue that making models fits within an inquiry approach - I'm just not sure that the model making itself suffices...

Update/Note: Flatbed scanners are a great way to get quick easy images of relatively small, relatively flat objects and the lighting is pretty good. The pasta DNA model above is the product of a scan, not a digital camera.

UPDATE - Revised lab sheets

Lost That Rhythm

Just when I was getting into a blogging rhythm, along came the end of the marking period grades, the beginning of the new semester where I am taking a course again, and now getting up early to go in and mark 8th grade science performance exams before school everyday for the next 2 weeks. Not surprisingly, with all the stress, I've caught a cold to slow me down when I need to speed up.

On the positive side, I just bought a laptop last week and I'm already wondering how I ever got along without it:

Dell Inspiron 600M

Pentium M 725 - 1.6 GHz, 14.1" screen

512M Ram

Intel PRO/Wireless 2915 Internal Wireless (802.11a/b/g54Mbps)

2 yrs tech support

etc....

$1,070.68 including tax & shipping

Nice, reasonably lightweight, reasonably fast - at least as fast as my (admittedly old) desktop at home. The internal wireless card is really nice, reception at home is much better than what I am getting from the older USB based stuff on my desktops. I have wireless access at my school and can hook the laptop to a projector and show animations and other useful web resources to the whole class.

I had been fishing around since early December, watching the prices go up & down, thinking a few times that I let the lowest price pass me by, but this price with 2 yrs tech support was the lowest I had seen for a while, so I took the bait. I checked everyday with gotapex - they post coupons and deals that are hard to find or non-existent on the Dell site itself. This particular deal was $500 off a $1499 or more Inspiron. I think the deal is still on.

I also purchased grading software (ThinkWave), after realizing this marking period that I can't possibly give grades based on weighted assignments by plugging numbers into a calculator - just too labor intensive. So I'm essentially tossing out the old paper & pencil binder with lesson plans, grades, attendance, and going high tech from now on. It may take a while to get the efficiency thing down, but what I was doing before just wasn't working for me.

January 2005 Regents

Hello, Annie Chien here. Guest Blogger, fellow science teacher. So my kids took the January 2005 exam - its part of SOF's effort to stick to authentic assessment. Let me explain...

SOF is a Coalition School (http://www.essentialschools.org/) that focuses on small classes, inquiry based learning/teacher as coach, less is more... While the school sees testing as ONE method of assessing for understanding, it believes that its not the ONLY way. So, for the Regents exams, we designed our curriculum so that the kids have enough knowledge to pass it in January so that they can focus on their research projects in June. This is easy since I see the same set of kids for two years in a row for 9th and 10th grade science (this design used to be called "housing").

SOF use to have a waiver for the Regents exams, but the State mandate took that away. The class of 2007 (who were my students and also the first set of students at SOF to take the Living Environments) had a 92% passing rate. This January, my students received a 97% passing rate (out of 100 students). Several thoughts came in mind. I think in bullets. So, here are my thoughts:

• The 97% is based on the curved score. The passing raw score was a 39 out of 85 possible points.
• Can they cheapen science education any futher?
• Yeah, so I read the exam. It was definitely tougher than most of the other exams. But, hey, I think I taught them enough material for them to all pass it without a curve. I think that the kids were mostly frustrated with the length of the exam. But hey, they really just needed to read each question carefully, then take a couple of extra steps to answer the questions.
• Okay, so it IS a curve and I'm sure their sampling methods were fine. So yeah, if you want to be optimistic, its a good passing rate compared with "others".

So what am I really saying here? I'm happy that my kids passed, but I also feel as though everyone got a free ride, even after all that practice we did, "Yeah, we'll scare you with all the Regents requirement hype, and make the curriculum rigorous like heck, but at the end, we'll just assess everyone on a curve, okay?"

Look, I'm proud of the science curriculum we've set at SOF, and okay, so we are so good at what we do that yes, we deserve such a high passing rate. I just wish I worked in a state where the curriculum and assessment made SENSE.

The exam gave me some ideas that can make my curriculum even more rigorous. Reproduction, genetics, biotechnology - hot topics that it focused on in addition to the usual ecology. We have already great project-based units that encompass the topics, and I'm brainstorming on elaborating on them even more.

After some post-exam group reflection, the kids tell me that the Regents Community review really helped. They said that the talking and listening to how problems were done by their peers helped them recall information better. To some extent, they admitted that my ass kicking (making practice homework count as a quiz, pop quizzes, calling parents) helped.

Regents are over, time to do some real fun science!

Pizza Party

I have a runnning competition going between my two regents classes. On quizzes, tests, exams, etc., I average the grades and keep a tally of their scores for the individual assessment, plus an overall score. They have been pretty close thoughout the year with one class slightly ahead of the other. Then came the midterm exam, for which I promised the winner a pizza party. And one class really walloped the other, winning by 12 points. Today they got their pizza party and needless to say, the other class cried foul. Nevermind that I've been on their case lately for not putting in the effort and not having what I consider to be a proper work ethic for an "honors" type, accelerated, grade 8 regents biology class.

As luck would have it, that second place group is also my official class, and there's the whole "familial" dynamic here makes them feel particularly slighted. I don't know yet how I will remedy the situation. I really like my official class, but a significant number of students just want to party - clown around, make jokes, socialize, etc. I can't just reward them for nothing. And the thing is their behavior/attitude problems are an issue in homeroom period as well, and their conduct sheet is far from perfect. I would love to be able to just reward the students who do work hard and succeed, but there is no clear divide between the two groups - if you lined the class up and put the worst offenders on one side and the hardest working best behaved student on the other side, everyone else would fall along a continuum between the extremes, with no clear demarcation point between those who deserve to be rewarded and those who don't. Then of course there's the slacker who does well on the exams, and the hard worker who doesn't quite get it yet and fails the exams. It's just an impossible split.

I will discuss the issue with them tomorrow and see if we can come up with a plan. They will need to do something to earn the pizza - I don't mind spending the money once in a while or using class time if they work hard enough to deserve it. If the exam scores had been closer and their lack of effort weren't so obvious, I would have given both classes a party today.